Wayland: Add support for pointer event frames

This adds support for wl_seat version 5, which adds pointer frames.
This allows two-dimensional scroll input to be emitted as single events
instead of one event per axis per motion.

It's also the the foundation for future enhancements like properly
scaled discrete scroll events and server-side key repeat.

Fixes #2494

CONTRIBUTORS.md

@@ -79,6 +79,7 @@ video tutorials.
  - Jason Francis
  - Gerald Franz
  - Mário Freitas
+ - Friz64
  - GeO4d
  - Marcus Geelnard
  - Gegy

README.md

@@ -150,6 +150,8 @@ information on what to include when reporting a bug.
    compositors without `pointer-constraints-unstable-v1`
  - [Wayland] Bugfix: Key repeat did not function on very old compositors
  - [Wayland] Bugfix: The `libwayland-client` library was not unloaded at termination
+ - [Wayland] Bugfix: Scroll events were sent twice on some versions of GNOME (#2494)
+ - [Wayland] Bugfix: Two-dimensional scroll input was emitted as separate axes
  - [X11] Bugfix: Running without a WM could trigger an assert (#2593,#2601,#2631)
  - [X11] Bugfix: Occasional crash when an idle display awakes (#2766) 
  - [X11] Bugfix: Prevent BadWindow when creating small windows with a content scale

src/wl_init.c

@@ -135,7 +135,7 @@ static void registryHandleGlobal(void* userData,
         {
             _glfw.wl.seat =
                 wl_registry_bind(registry, name, &wl_seat_interface,
-                                 _glfw_min(4, version));
+                                 _glfw_min(5, version));
             _glfwAddSeatListenerWayland(_glfw.wl.seat);
         }
     }

src/wl_platform.h

@@ -414,7 +414,8 @@ typedef struct _GLFWwindowWayland
         GLFWbool                    decorations;
         struct wl_buffer*           buffer;
         _GLFWfallbackEdgeWayland    top, left, right, bottom;
-        wl_fixed_t                  pointerX, pointerY;
+        double                      pointerX, pointerY;
+        uint32_t                    buttonPressSerial;
         const char*                 cursorName;
     } fallback;
 } _GLFWwindowWayland;
@@ -472,6 +473,17 @@ typedef struct _GLFWlibraryWayland
     short int                   scancodes[GLFW_KEY_LAST + 1];
     char                        keynames[GLFW_KEY_LAST + 1][5];
 
+    struct {
+        struct wl_surface*      pointerSurface;
+        unsigned int            events;
+        double                  pointerX;
+        double                  pointerY;
+        double                  scrollX;
+        double                  scrollY;
+        int                     button;
+        int                     action;
+    } pending;
+
     struct {
         void*                   handle;
         struct xkb_context*     context;

src/wl_window.c

@@ -55,6 +55,11 @@
 #define GLFW_BORDER_SIZE    4
 #define GLFW_CAPTION_HEIGHT 24
 
+#define GLFW_PENDING_SURFACE 1
+#define GLFW_PENDING_BUTTON  2
+#define GLFW_PENDING_MOTION  4
+#define GLFW_PENDING_SCROLL  8
+
 static int createTmpfileCloexec(char* tmpname)
 {
     int fd;
@@ -278,15 +283,11 @@ static void destroyFallbackDecorations(_GLFWwindow* window)
     destroyFallbackEdge(&window->wl.fallback.bottom);
 }
 
-static void updateFallbackDecorationCursor(_GLFWwindow* window,
-                                           wl_fixed_t sx,
-                                           wl_fixed_t sy)
+static void updateFallbackDecorationCursor(_GLFWwindow* window, double xpos, double ypos)
 {
-    window->wl.fallback.pointerX = sx;
-    window->wl.fallback.pointerY = sy;
+    window->wl.fallback.pointerX = xpos;
+    window->wl.fallback.pointerY = ypos;
 
-    const double xpos = wl_fixed_to_double(sx);
-    const double ypos = wl_fixed_to_double(sy);
     const char* cursorName = "left_ptr";
 
     if (window->resizable)
@@ -361,18 +362,16 @@ static void updateFallbackDecorationCursor(_GLFWwindow* window,
     }
 }
 
-static void handleFallbackDecorationButton(_GLFWwindow* window,
-                                           uint32_t serial,
-                                           uint32_t button,
-                                           uint32_t state)
+static void handleFallbackDecorationButton(_GLFWwindow* window, int button, int action)
 {
-    if (state != WL_POINTER_BUTTON_STATE_PRESSED)
+    if (action != GLFW_PRESS)
         return;
 
-    const double xpos = wl_fixed_to_double(window->wl.fallback.pointerX);
-    const double ypos = wl_fixed_to_double(window->wl.fallback.pointerY);
+    const double xpos = window->wl.fallback.pointerX;
+    const double ypos = window->wl.fallback.pointerY;
+    const uint32_t serial = window->wl.fallback.buttonPressSerial;
 
-    if (button == BTN_LEFT)
+    if (button == GLFW_MOUSE_BUTTON_LEFT)
     {
         uint32_t edges = XDG_TOPLEVEL_RESIZE_EDGE_NONE;
 
@@ -410,7 +409,7 @@ static void handleFallbackDecorationButton(_GLFWwindow* window,
         if (edges != XDG_TOPLEVEL_RESIZE_EDGE_NONE)
             xdg_toplevel_resize(window->wl.xdg.toplevel, _glfw.wl.seat, serial, edges);
     }
-    else if (button == BTN_RIGHT)
+    else if (button == GLFW_MOUSE_BUTTON_RIGHT)
     {
         if (!window->wl.xdg.toplevel)
             return;
@@ -421,10 +420,8 @@ static void handleFallbackDecorationButton(_GLFWwindow* window,
         if (ypos < GLFW_BORDER_SIZE)
             return;
 
-        xdg_toplevel_show_window_menu(window->wl.xdg.toplevel,
-                                      _glfw.wl.seat, serial,
-                                      xpos,
-                                      ypos - GLFW_CAPTION_HEIGHT - GLFW_BORDER_SIZE);
+        xdg_toplevel_show_window_menu(window->wl.xdg.toplevel, _glfw.wl.seat, serial,
+                                      xpos, ypos - GLFW_CAPTION_HEIGHT - GLFW_BORDER_SIZE);
     }
 }
 
@@ -1538,25 +1535,39 @@ static void pointerHandleEnter(void* userData,
 
     _glfw.wl.serial = serial;
     _glfw.wl.pointerEnterSerial = serial;
-    _glfw.wl.pointerSurface = surface;
 
     _GLFWwindow* window = wl_surface_get_user_data(surface);
-    if (window->wl.surface == surface)
-    {
-        _glfwSetCursorWayland(window, window->cursor);
-        _glfwInputCursorEnter(window, GLFW_TRUE);
+    const double xpos = wl_fixed_to_double(sx);
+    const double ypos = wl_fixed_to_double(sy);
 
-        if (window->cursorMode != GLFW_CURSOR_DISABLED)
-        {
-            window->wl.cursorPosX = wl_fixed_to_double(sx);
-            window->wl.cursorPosY = wl_fixed_to_double(sy);
-            _glfwInputCursorPos(window, window->wl.cursorPosX, window->wl.cursorPosY);
-        }
+    if (wl_pointer_get_version(pointer) >= WL_POINTER_FRAME_SINCE_VERSION)
+    {
+        _glfw.wl.pending.events |= (GLFW_PENDING_SURFACE | GLFW_PENDING_MOTION);
+        _glfw.wl.pending.pointerSurface = surface;
+        _glfw.wl.pending.pointerX = xpos;
+        _glfw.wl.pending.pointerY = ypos;
     }
     else
     {
-        if (window->wl.fallback.decorations)
-            updateFallbackDecorationCursor(window, sx, sy);
+        _glfw.wl.pointerSurface = surface;
+
+        if (window->wl.surface == _glfw.wl.pointerSurface)
+        {
+            _glfwSetCursorWayland(window, window->cursor);
+            _glfwInputCursorEnter(window, GLFW_TRUE);
+
+            if (window->cursorMode != GLFW_CURSOR_DISABLED)
+            {
+                window->wl.cursorPosX = xpos;
+                window->wl.cursorPosY = ypos;
+                _glfwInputCursorPos(window, window->wl.cursorPosX, window->wl.cursorPosY);
+            }
+        }
+        else
+        {
+            if (window->wl.fallback.decorations)
+                updateFallbackDecorationCursor(window, xpos, ypos);
+        }
     }
 }
 
@@ -1572,15 +1583,25 @@ static void pointerHandleLeave(void* userData,
         return;
 
     _glfw.wl.serial = serial;
-    _glfw.wl.pointerSurface = NULL;
 
     _GLFWwindow* window = wl_surface_get_user_data(surface);
-    if (window->wl.surface == surface)
-        _glfwInputCursorEnter(window, GLFW_FALSE);
+
+    if (wl_pointer_get_version(pointer) >= WL_POINTER_FRAME_SINCE_VERSION)
+    {
+        _glfw.wl.pending.events |= GLFW_PENDING_SURFACE;
+        _glfw.wl.pending.pointerSurface = NULL;
+    }
     else
     {
-        if (window->wl.fallback.decorations)
-            window->wl.fallback.cursorName = NULL;
+        _glfw.wl.pointerSurface = NULL;
+
+        if (window->wl.surface == surface)
+            _glfwInputCursorEnter(window, GLFW_FALSE);
+        else
+        {
+            if (window->wl.fallback.decorations)
+                window->wl.fallback.cursorName = NULL;
+        }
     }
 }
 
@@ -1594,20 +1615,28 @@ static void pointerHandleMotion(void* userData,
         return;
 
     _GLFWwindow* window = wl_surface_get_user_data(_glfw.wl.pointerSurface);
-
     if (window->cursorMode == GLFW_CURSOR_DISABLED)
         return;
 
-    if (window->wl.surface == _glfw.wl.pointerSurface)
+    const double xpos = wl_fixed_to_double(sx);
+    const double ypos = wl_fixed_to_double(sy);
+
+    if (wl_pointer_get_version(pointer) >= WL_POINTER_FRAME_SINCE_VERSION)
     {
-        window->wl.cursorPosX = wl_fixed_to_double(sx);
-        window->wl.cursorPosY = wl_fixed_to_double(sy);
-        _glfwInputCursorPos(window, window->wl.cursorPosX, window->wl.cursorPosY);
+        _glfw.wl.pending.events |= GLFW_PENDING_MOTION;
+        _glfw.wl.pending.pointerX = xpos;
+        _glfw.wl.pending.pointerY = ypos;
     }
     else
     {
-        if (window->wl.fallback.decorations)
-            updateFallbackDecorationCursor(window, sx, sy);
+        if (window->wl.surface == _glfw.wl.pointerSurface)
+        {
+            window->wl.cursorPosX = xpos;
+            window->wl.cursorPosY = ypos;
+            _glfwInputCursorPos(window, window->wl.cursorPosX, window->wl.cursorPosY);
+        }
+        else
+            updateFallbackDecorationCursor(window, xpos, ypos);
     }
 }
 
@@ -1615,27 +1644,39 @@ static void pointerHandleButton(void* userData,
                                 struct wl_pointer* pointer,
                                 uint32_t serial,
                                 uint32_t time,
-                                uint32_t button,
+                                uint32_t buttonID,
                                 uint32_t state)
 {
     if (!_glfw.wl.pointerSurface)
         return;
 
+    _glfw.wl.serial = serial;
+
     _GLFWwindow* window = wl_surface_get_user_data(_glfw.wl.pointerSurface);
+    const int button = buttonID - BTN_LEFT;
+    const int action = (state == WL_POINTER_BUTTON_STATE_PRESSED);
 
-    if (window->wl.surface == _glfw.wl.pointerSurface)
+    if (window->wl.fallback.decorations)
     {
-        _glfw.wl.serial = serial;
+        if (action == GLFW_PRESS)
+            window->wl.fallback.buttonPressSerial = serial;
+    }
 
-        _glfwInputMouseClick(window,
-                             button - BTN_LEFT,
-                             state == WL_POINTER_BUTTON_STATE_PRESSED,
-                             _glfw.wl.xkb.modifiers);
+    if (wl_pointer_get_version(pointer) >= WL_POINTER_FRAME_SINCE_VERSION)
+    {
+        _glfw.wl.pending.events |= GLFW_PENDING_BUTTON;
+        _glfw.wl.pending.button = button;
+        _glfw.wl.pending.action = action;
     }
     else
     {
-        if (window->wl.fallback.decorations)
-            handleFallbackDecorationButton(window, serial, button, state);
+        if (window->wl.surface == _glfw.wl.pointerSurface)
+            _glfwInputMouseClick(window, button, action, _glfw.wl.xkb.modifiers);
+        else
+        {
+            if (window->wl.fallback.decorations)
+                handleFallbackDecorationButton(window, button, action);
+        }
     }
 }
 
@@ -1649,8 +1690,18 @@ static void pointerHandleAxis(void* userData,
         return;
 
     _GLFWwindow* window = wl_surface_get_user_data(_glfw.wl.pointerSurface);
+    if (window->wl.surface != _glfw.wl.pointerSurface)
+        return;
 
-    if (window->wl.surface == _glfw.wl.pointerSurface)
+    if (wl_pointer_get_version(pointer) >= WL_POINTER_FRAME_SINCE_VERSION)
+    {
+        _glfw.wl.pending.events |= GLFW_PENDING_SCROLL;
+        if (axis == WL_POINTER_AXIS_HORIZONTAL_SCROLL)
+            _glfw.wl.pending.scrollX = -wl_fixed_to_double(value) / 10.0;
+        else if (axis == WL_POINTER_AXIS_VERTICAL_SCROLL)
+            _glfw.wl.pending.scrollY = -wl_fixed_to_double(value) / 10.0;
+    }
+    else
     {
         // NOTE: 10 units of motion per mouse wheel step seems to be a common ratio
         if (axis == WL_POINTER_AXIS_HORIZONTAL_SCROLL)
@@ -1660,6 +1711,109 @@ static void pointerHandleAxis(void* userData,
     }
 }
 
+static void pointerHandleFrame(void* userData, struct wl_pointer* pointer)
+{
+    if (_glfw.wl.pending.events & GLFW_PENDING_SURFACE)
+    {
+        if (_glfw.wl.pointerSurface)
+        {
+            _GLFWwindow* window = wl_surface_get_user_data(_glfw.wl.pointerSurface);
+            if (window->wl.surface == _glfw.wl.pointerSurface)
+                _glfwInputCursorEnter(window, GLFW_FALSE);
+            else
+            {
+                if (window->wl.fallback.decorations)
+                    window->wl.fallback.cursorName = NULL;
+            }
+        }
+
+        _glfw.wl.pointerSurface = _glfw.wl.pending.pointerSurface;
+
+        if (_glfw.wl.pointerSurface)
+        {
+            _GLFWwindow* window = wl_surface_get_user_data(_glfw.wl.pointerSurface);
+            if (window->wl.surface == _glfw.wl.pointerSurface)
+            {
+                _glfwSetCursorWayland(window, window->cursor);
+                _glfwInputCursorEnter(window, GLFW_TRUE);
+            }
+        }
+    }
+
+    if (!_glfw.wl.pointerSurface)
+        return;
+
+    _GLFWwindow* window = wl_surface_get_user_data(_glfw.wl.pointerSurface);
+
+    if (_glfw.wl.pending.events & GLFW_PENDING_MOTION)
+    {
+        if (window->wl.surface == _glfw.wl.pointerSurface)
+        {
+            window->wl.cursorPosX = _glfw.wl.pending.pointerX;
+            window->wl.cursorPosY = _glfw.wl.pending.pointerY;
+            _glfwInputCursorPos(window, window->wl.cursorPosX, window->wl.cursorPosY);
+        }
+        else
+        {
+            updateFallbackDecorationCursor(window,
+                                           _glfw.wl.pending.pointerX,
+                                           _glfw.wl.pending.pointerY);
+        }
+    }
+
+    if (_glfw.wl.pending.events & GLFW_PENDING_BUTTON)
+    {
+        if (window->wl.surface == _glfw.wl.pointerSurface)
+        {
+            _glfwInputMouseClick(window,
+                                 _glfw.wl.pending.button,
+                                 _glfw.wl.pending.action,
+                                 _glfw.wl.xkb.modifiers);
+        }
+        else
+        {
+            if (window->wl.fallback.decorations)
+            {
+                handleFallbackDecorationButton(window,
+                                               _glfw.wl.pending.button,
+                                               _glfw.wl.pending.action);
+            }
+        }
+    }
+
+    if (_glfw.wl.pending.events & GLFW_PENDING_SCROLL)
+    {
+        if (window->wl.surface == _glfw.wl.pointerSurface)
+        {
+            _glfwInputScroll(window,
+                             _glfw.wl.pending.scrollX,
+                             _glfw.wl.pending.scrollY);
+        }
+    }
+
+    memset(&_glfw.wl.pending, 0, sizeof(_glfw.wl.pending));
+}
+
+static void pointerHandleAxisSource(void* userData,
+                                    struct wl_pointer* pointer,
+                                    uint32_t axisSource)
+{
+}
+
+static void pointerHandleAxisStop(void* userData,
+                                  struct wl_pointer* pointer,
+                                  uint32_t time,
+                                  uint32_t axis)
+{
+}
+
+static void pointerHandleAxisDiscrete(void* userData,
+                                      struct wl_pointer* pointer,
+                                      uint32_t axis,
+                                      int32_t discrete)
+{
+}
+
 static const struct wl_pointer_listener pointerListener =
 {
     pointerHandleEnter,
@@ -1667,6 +1821,10 @@ static const struct wl_pointer_listener pointerListener =
     pointerHandleMotion,
     pointerHandleButton,
     pointerHandleAxis,
+    pointerHandleFrame,
+    pointerHandleAxisSource,
+    pointerHandleAxisStop,
+    pointerHandleAxisDiscrete
 };
 
 static void keyboardHandleKeymap(void* userData,